how do i bend a custom object
You had the right idea with the Curve modifier and Bezier Curve. It looks to me like it's not working because the origin points of both objects are off in some arbitrary location. Set the origin point of your Curve to be at the start of the curve path. Set the origin point of your mesh object to be on the edge of your mesh. Then add the Curve modifier. You may need to fiddle with the axes depending on the rotation of your objects (it's easier if both the Curve and Mesh are oriented in the same direction from the start). Once the modifier is on, you can just grab the mesh along the applicable axis and it will slide along the curve. You may need to have a SubSurf modifier preceding your Curve modifier in your stack in order for it to have enough mesh density to deform well. I my screen shot note the position of the 3D cursor - this is also the origin point of both of my objects. Since I'm in Edit Mode you can see that the wireframe represents the original location of the mesh object, and the bent version is the position after the modifier is added.